mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-01 12:03:41 +00:00
5144c22189
- Use nullness checks when calling weakly linked functions. - Avoid typedef for reasons described in Linux Kernel style guide. - Avoid enum in in Windows headers. Earlier in Cosmo's history all one hundred files in libc/nt/enum/ used to be enums and it resulted in gigabytes of DWARF data almost as large as everything else in the codebase combined. - Bitfields aren't our friends. They have frequent ABI breakages, inconsistent arithmetic across compilers, and different endianness between cpus. Compiler authors also haven't invested much roi into making bit fields go fast so they produce poor assembly. - Use memccpy() instead of strncpy() or snprintf() for length-bounded copying of C strings. strncpy() is a misunderstood function and snprintf() is awesome but memccpy() deserves more love.
112 lines
5.2 KiB
C
112 lines
5.2 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ This is free and unencumbered software released into the public domain. │
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│ │
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│ Anyone is free to copy, modify, publish, use, compile, sell, or │
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│ distribute this software, either in source code form or as a compiled │
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│ binary, for any purpose, commercial or non-commercial, and by any │
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│ means. │
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│ │
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│ In jurisdictions that recognize copyright laws, the author or authors │
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│ of this software dedicate any and all copyright interest in the │
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│ software to the public domain. We make this dedication for the benefit │
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│ of the public at large and to the detriment of our heirs and │
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│ successors. We intend this dedication to be an overt act of │
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│ relinquishment in perpetuity of all present and future rights to this │
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│ software under copyright law. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
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│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
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│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
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│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR │
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│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, │
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│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR │
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│ OTHER DEALINGS IN THE SOFTWARE. │
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│ │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/safemacros.internal.h"
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#include "libc/calls/calls.h"
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#include "libc/dns/consts.h"
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#include "libc/dns/dns.h"
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#include "libc/dns/hoststxt.h"
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#include "libc/dns/resolvconf.h"
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#include "libc/fmt/conv.h"
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#include "libc/fmt/fmt.h"
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#include "libc/fmt/itoa.h"
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#include "libc/mem/mem.h"
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#include "libc/sock/sock.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/af.h"
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#include "libc/sysv/consts/inaddr.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Resolves name/service for socket address.
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*
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* @param addr
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* @param addrlen
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* @param name
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* @param namelen
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* @param service
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* @param servicelen
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* @param flags
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*
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* @return 0 on success or EAI_xxx value
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*/
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int getnameinfo(const struct sockaddr *addr, socklen_t addrlen, char *name,
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socklen_t namelen, char *service, socklen_t servicelen,
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int flags) {
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char *p, rdomain[1 + sizeof "255.255.255.255.in-addr.arpa"];
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char info[512];
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int rc, port;
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uint8_t *ip;
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unsigned int valid_flags;
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valid_flags =
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(NI_NAMEREQD | NI_NUMERICHOST | NI_NUMERICSERV | NI_NOFQDN | NI_DGRAM);
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if (flags & ~(valid_flags)) return EAI_BADFLAGS;
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if (!name && !service) return EAI_NONAME;
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if (addr->sa_family != AF_INET || addrlen < sizeof(struct sockaddr_in))
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return EAI_FAMILY;
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ip = (uint8_t *)&(((struct sockaddr_in *)addr)->sin_addr);
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p = rdomain;
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p += int64toarray_radix10(ip[3], p), *p++ = '.';
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p += int64toarray_radix10(ip[2], p), *p++ = '.';
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p += int64toarray_radix10(ip[1], p), *p++ = '.';
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p += int64toarray_radix10(ip[0], p), stpcpy(p, ".in-addr.arpa");
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info[0] = '\0';
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if (name != NULL && namelen != 0) {
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if ((flags & NI_NUMERICHOST) && (flags & NI_NAMEREQD)) return EAI_NONAME;
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if ((flags & NI_NUMERICHOST) &&
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inet_ntop(AF_INET, ip, info, sizeof(info)) == NULL)
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return EAI_SYSTEM;
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else if (!info[0] && ResolveHostsReverse(GetHostsTxt(), AF_INET, ip, info,
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sizeof(info)) < 0)
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return EAI_SYSTEM;
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else if (!info[0] && ResolveDnsReverse(GetResolvConf(), AF_INET, rdomain,
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info, sizeof(info)) < 0)
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return EAI_SYSTEM;
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else if (!info[0] && (flags & NI_NAMEREQD))
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return EAI_NONAME;
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else if (!info[0] && inet_ntop(AF_INET, ip, info, sizeof(info)) == NULL)
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return EAI_SYSTEM;
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if (strlen(info) + 1 > namelen) return EAI_OVERFLOW;
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strcpy(name, info);
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}
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port = ntohs(((struct sockaddr_in *)addr)->sin_port);
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info[0] = '\0';
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if (service != NULL && servicelen != 0) {
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itoa(port, info, 10);
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/* TODO: reverse lookup on /etc/services to get name of service */
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if (strlen(info) + 1 > servicelen) return EAI_OVERFLOW;
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strcpy(service, info);
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}
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return 0;
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}
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